Press-fit Technique Research Articles

Assessment of Treatment Approaches for Oroantral Communication and Fistulas

Objective: The aim of this study was to investigate and compare the treatment methods of large size oroantral defects (OADs) and their clinical outcomes. Material and Methods: The patients who referred our clinic between 2017 and 2023 suffering from oroantral fistula (OAF) and the cases which was occurred oroantral communication (OAC) larger than 5mm during oral procedures were included in the study. The size, type and cause of OAD, treatment method, the patient’s demographic data was recorded. VAS scale, analgesic requirement, the edema, and mouth opening measurements were obtained from preoperative day and postoperative records at 3, 7, 10 days after surgery. Results: 23 patient (8 OAF, 15 OAC) was included in this study. 9 of them was treated with buccal advancement flap (BAF), 10 with buccal fat pad (BFP) and 4 with press-fit technique. No problem was occurred at the healing process. Only in one patient BFP application was failed, and after 2 months second surgery was performed, and the area was fully covered. According to postoperative clinical outcomes, any statistically significance wasn’t observed between groups in the terms of vas scale, analgesic requirement, edema and trismus at any timepoint (p 0.05). Although there was insignificance at all parameters between treatment groups, VAS scale and analgesic requirement was less than BAF and BFP in press fit. Conclusion: BAF, BFP and press-fit methods are reliable and well-known techniques for OAD management, however, further clinical studies with larger sample sizes are needed to create treatment algorithm for OAD.

Effect of Press-Fit Size on Insertion Mechanics and Cartilage Viability in Human and Ovine Osteochondral Grafts.

The osteochondral allograft procedure uses grafts constructed larger than the recipient site to stabilize the graft, in what is known as the press-fit technique. This research aims to characterize the relationships between press-fit size, insertion forces, and cell viability in ovine and human osteochondral tissue. Human (4 donors) and ovine (5 animals) articular joints were used to harvest osteochondral grafts (4.55 mm diameter, N = 33 Human, N = 35 Ovine) and create recipient sites with grafts constructed to achieve varying degrees of press fit (0.025-0.240 mm). Donor grafts were inserted into recipient sites while insertion forces were measured followed by quantification of chondrocyte viability and histological staining to evaluate the extracellular matrix. Both human and ovine tissues exhibited similar mechanical and cellular responses to changes in press-fit. Insertion forces (Human: 3-169 MPa, Ovine: 36-314 MPa) and cell viability (Human: 16%-89% live, Ovine: 2%-76% live) were correlated to press-fit size for both human (force: r = 0.539, viability: r = -0.729) and ovine (force: r = 0.655, viability: r = -0.714) tissues. In both species, a press-fit above 0.14 mm resulted in reduced cell viability below a level acceptable for transplantation, increased insertion forces, and reduced linear correlation to press-fit size compared to samples with a press-fit below 0.14 mm. Increasing press-fit size required increased insertion forces and resulted in reduced cell viability. Ovine and human osteochondral tissues responded similarly to impact insertion and varying press-fit size, providing evidence for the use of the ovine model in allograft-related research.

Differences in acoustic parameters of hammering sounds between successful and unsuccessful initial cementless cup press-fit fixation in total hip arthroplasty.

It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation.

Tibial Press-Fit Fixation Technique in Anterior Cruciate Ligament Reconstruction Surgery

Implant-free press-fit tibial fixation technique has recently gained popularity in anterior cruciate ligament reconstruction because it does not cause tunnel widening, does not cause complications associated with additional fixation materials, allows bone-to-bone healing, and does not cause defects in revision surgery. Bone-patellar tendon autograft offers the advantage of direct bone-to-bone integration of the graft, and anterior knee pain is less expected than bone-patellar tendon-bone autograft. This technical report includes details of arthroscopic ACL reconstruction of patellar tendon-tibial tubercle bone autograft distal press-fit fixation technique. We call this the Kocabey distal press-fit technique.

The press-fit technique without screws and bone graft can be used as an alternative method in Crowe type II and III hip dysplasia.

Developmental dysplasia of the hip (DDH) is the most common cause of secondary hip arthrosis. The primary purpose of this study was to assess the results of an oversized hemispherical cup via the press-fit technique used for Crowe type II and III DDH without screws and to determine if adequate medialization and initial stability of the acetabular component would allow us to avoid screw and graft use. Between February 2012 and May 2020, the current study analyzed 43 hips with Crowe type II and III DDH treated with a porous-coated cup by placing the press-fit technique or screw. The acetabular cup was fixed with the press-fit technique without additional screws in 27 hips and with screws in 16 hips. The inclusion criterion in this study was a minimum 2-year-period after the surgery. The mean duration of follow-up was 6.83 ± 2.67 years in the press-fit group and 6.21 ± 2.01 years in the screw group. The mean age of the patients was 47.96 ± 12.37 years in the press-fit group and 50.5 ± 12.37 years in the screw group. Measurements revealed that the hip center of rotation (HCR) was located more medially and superiorly postoperatively than preoperatively in both groups. The mean cup coverage in the screw group was 85.58% ± 7.51% (75.3%-97.2%), while it was less than 90.41% ± 6.15% (76.3%-98.2%) in the press-fit group (p = 0.038). No component was revised because of loosening, and all of the implants were radiologically stable within the observation period. No statistically significant differences were observed regarding the postoperative limp-length discrepancy between the groups (p = 0.496). Press-fit implantation of a porous-coated acetabular component without screws can also be used as an alternative method for THA in Crowe type II and III DDH. The initial stability was obtained using the press-fit technique with a small cup positioned more medially and superiorly, which may allow the surgeon to avoid screw and graft use.

Osteochondral Allograft and Concurrent Meniscal Allograft Transplantation

Background: Symptomatic, full-thickness chondral defects often are associated with meniscal deficiencies. These are difficult problems to manage in the young, high-demand patient population. A number of differing techniques have been published with no consensus. While more recent techniques have favored minimally invasive approaches, an open approach with tubercle osteotomy to maximize visualization of all knee compartments can still provide favorable outcomes when using a careful technique and postoperative protocol. Indications: Young, high-demand patients with long-standing meniscal deficiency and resultant chondral defects are indicated for cartilage restoration and preservation procedures. A meniscal allograft transplantation is indicated in symptomatic patients with prior total or subtotal meniscectomy. It is important to address other concomitant pathology such as instability, alignment, and chondral defects. Concomitant procedures are often performed with meniscal transplants, including osteochondral allograft transplantation for larger defects. Technique Description: This surgical technique video demonstrates a tibial tubercle osteotomy approach to gain access to both the medial and lateral tibiofemoral compartments. An arthroscopic-assisted bone slot technique was performed for meniscal allograft transplantation. Appropriately sized osteochondral allograft bone plugs were then transplanted onto the medial and femoral condyles with a press fit technique. Results: At 1-year follow-up, the presented patient has regained full motion and are back to full activities. Discussion/Conclusion: Full-thickness chondral defects associated with meniscal deficiency in a young, high-demand patient is a difficult problem to manage. Recent results using minimally invasive approaches have demonstrated favorable mid- and long-term outcomes. In patients with pathology that may preclude a minimally invasive approach, an open technique with osteotomy can still have a promising outcome. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

REMOVAL OF PRESS-FIT TRANSTIBIAL OSSEOINTEGRATION IMPLANTS

IntroductionApproximately 2,000 Skeletal transcutaneous osseointegration (STOI) procedures have been performed worldwide as of 2020, more than half of which have been performed by the Osseointegration Group of Australia using a press-fit technique with either ILP or OPL implant designs. Despite the consistently demonstrated clinical benefits, concerns regarding potential complications following STOI have slowed its widespread adoption. As more patients are followed for a longer period of time, longitudinal studies have confirmed complication rates are very acceptable, similar to those of total ankle and total elbow replacements. One of the major risk category is implant removal. The primary goal of this study was to investigate the complications and technical issues associated with transtibial osseointegration implant removal due to any cause. The focus here will be on the press-fit ILP and OPL implants, including the indications for removal and patient outcomes following removal.Materials &amp; MethodsA review of our osseointegration registry between November 2010 and March 2022 was performed. Inclusion criteria were patients who have undergone removal of a transtibial osseointegration implant due to any cause. Selected patients either had a follow-up of at least two years or had their index osseointegration surgery at least two years prior to when the study was performed. Patients who have had osseointegration at other anatomic levels, and patients who underwent simultaneous total knee replacement with transtibial osseointegration were excluded from the registry search.ResultsThere were a total of 148 transtibial osseointegration procedures performed during the study period, with 97 (65.5%) performed in males and 51 (34.5%) performed in females. The average age at first stage osseointegration procedure is 50.4 years (range 16.8–87.9, SD 14.1). In the study cohort of 22 cases requiring implant removals, 12 (54.5%) were male and 10 (45.5%) were female. The average age at first stage osseointegration procedure in this cohort is 51.3 (range 37.4–82.6, SD 10.7) and average BMI 30.3 (range 21.9–40.9, SD 5.8). Although men comprised the majority of removals, women had a greater relative risk (Fisher exact test p=0.032). The average duration from time of STOI to removal was 2.6 years (range 0.1–6.8, SD 1.9) within this 11.5 year follow-up period. The most frequent indication was infection (54.6%, n=12) followed equally by pain (13.6%, n=3), aseptic loosening (13.6%, n=3) and implant fracture (13.6%, n=3), and lastly failure to integrate (4.6%, n=1).ConclusionsOf the 22 removals, 12 were reimplanted at the same anatomical level (10 were reimplanted within 6 months, 1 within 12 months, and 1 within 24 months). 11 of these cases currently wear their prosthetic legs for more than 13 hours daily. 1 case was recently reimplanted and still completing their loading program. Of the patients who were not reimplanted at the same anatomical level, 1 required proximal amputation with transfemoral osseointegration. 3 patients converted to traditional socket prostheses (TSP) due to pain, and 1 underwent proximal amputation and converted to TSP due to infection. 3 cases are currently awaiting transtibial osseointegration reimplantation, and 1 patient was deceased. 1 patient was lost to follow-up.

Tibial Press-Fit Fixation Technique in Anterior Cruciate Ligament Reconstruction

Implant-free press-fit tibial fixation technique has gained popularity recently due to the problems in bone tunnel expansion, defect, and revision surgery due to the tibial fixation material preferred in anterior cruciate ligament surgery. Patellar tendon-tibial bone autograft offers several advantages in anterior cruciate ligament reconstruction. We describe a tibial tunnel preparation method and the use of patellar tendon-bone graft in the implant-free tibial press-fit technique. We call this the Kocabey press-fit technique.

Thermally stable multi-directional magnetoelectric based embedded magnetic sensor

Owing to the multifunctional behavior possessed by magnetoelectric (ME) composites, they are sought-after materials for various magnetic field sensing applications. This article proposes a three-directional ME-based embedded magnetic sensor that has been fabricated using the press-fit technique. The employed fabrication method negates the use of epoxy in the ME sensor, thus enabling its use at elevated temperatures in excess of 100 ∘C. The fabricated sensor is tested using an experimental setup capable of producing ac and dc bias magnetic fields in three coordinate directions. Experiments are performed for various dc magnetic field conditions, including x, y, z directions, their simultaneous combinations, and magnetic field aligned at an angle with the sensor. Under all testing conditions, the embedded sensor shows a significantly high output voltage response. Additionally, the effect of the magnetic field generated by the double magnet system and single magnet system on the sensor performance has also been demonstrated, wherein the embedded sensor is observed to be marginally affected by magnetic field due to the presence of only one magnet. Finally, quasi-static ME measurements are performed at elevated temperatures up to 100 ∘C, and it is observed that the novel embedded sensor has reliable sensing capabilities in aggravated thermal environments even in excess of 100 ∘C. Thus, the proposed three-directional embedded magnetic sensor offers reliable response under all conditions of magnetic field and temperature and can thus be a reliable alternative for the traditionally used layered-based counterparts.

Low Femoral Tunnel Widening Incidence Rate After ACL Reconstruction Using Patellar Tendon Graft with Press-Fit Fixation

BackgroundFemoral tunnel widening after ACL reconstruction is a common phenomenon. We hypothesized that using a patellar tendon graft with a press-fit fixation technique without any fixation device reduces the incidence of femoral tunnel widening.MethodsThis study was conducted on 467 patients with ACL surgery between 2003 and 2015. Two hundred and nineteen of them had an ACL surgery with patellar tendon (PT) graft, and two hundred and forty-eight of them with hamstring tendon (HS). Exclusion criteria were history of previous ACL reconstruction of either knee, multiple ligament injury, or evidence of osteoarthritis on radiographs. The femoral tunnels were measured on the anteroposterior (ap) and lateral radiographs 6 months after the operation. Two independent orthopedic surgeons measured all radiographs twice and recorded the tunnel widenings. We hypothesized that using an implant-free press-fit technique with PT graft can reduce the femoral tunnel widening incidence rate.ResultsThe mean incidence rate of the tunnel widening in the HS group was, on the AP and the lateral femoral views, 88% (n = 217) and 83% (n = 205), while in the PT group, 17% (n = 37) and 2% (n = 4), respectively. There was a significant difference both on AP and lateral radiographs (HS vs. PT: fem. AP: 89% vs. 17% p < 0.001; HS vs. PT: fem. lat: 84% vs. 2% p < 0.001).ConclusionThe femoral tunnel widening incidence rate during an ACL reconstruction is significantly less when using PT tendon with femoral press-fit fixation than when using HT tendon with suspensory fixation method.

Fresh Femoral Osteochondral Allograft Transplantation Using a Single-Plug Technique for Large Osteochondral Defects of the Knee

Osteochondral allograft (OCA) transplantation has been used to treat a wide spectrum of cartilage deficiencies in the knee, including spontaneous necrosis of the knee. Studies reporting outcomes after OCA transplantation have shown reliable improvement in pain and return to activities of daily living. We describe a single-plug, press-fit technique for OCA transplantation with concomitant high tibial osteotomy to treat femoral condyle chondral defects in a varus knee. Pearls and pitfalls of this technique are presented; attention should be paid to correction of concomitant joint pathology and malalignment to facilitate osseointegration and survivorship of the allograft plug into host bone. Appropriate surgical timing and prompt allograft implantation help to maximize chondrocyte viability.

Talar OsteoPeriostic grafting from the Iliac Crest (TOPIC) for lateral osteochondral lesions of the talus: operative technique.

To provide anatural scaffold, good quality cells, and growth factors to facilitate replacement of the complete osteochondral unit with matching talar curvature for large osteochondral lesions of the lateral talar dome. Symptomatic primary and non-primary lateral osteochondral lesions of the talus not responding to conservative treatment. The anterior-posterior or medial-lateral diameter should exceed 10 mm on computed tomography (CT) for primary lesions; for secondary lesions, there are no size limitations. Tibiotalar osteoarthritis gradeIII, malignancy, active infectious ankle joint pathology, and hemophilic or other diffuse arthropathy. Anterolateral arthrotomy is performed after which the Anterior TaloFibular Ligament (ATFL) is disinserted from the fibula. Additional exposure is achieved by placing aHintermann distractor subluxating the talus ventrally. Thereafter, the osteochondral lesion is excised in toto from the talar dome. The recipient site is micro-drilled in order to disrupt subchondral bone vessels. Thereafter, the autograft is harvested from the ipsilateral iliac crest with an oscillating saw, after which the graft is adjusted to an exactly fitting shape to match the extracted lateral osteochondral defect and the talar morphology as well as curvature. The graft is implanted with apress-fit technique after which the ATFL is re-inserted followed by potential augmentation with an InternalBrace™ (Arthrex, Naples, FL, USA). Non-weightbearing cast for 6weeks, followed by another 6weeks with awalking boot. After 12weeks, acomputed tomography (CT) scan is performed to assess consolidation of the inserted autograft. The patient is referred to aphysiotherapist.

HOW MUCH STABILITY DO WE NEED IN THE 1 MM PRESS-FIT IMPLANTATION OF A POROUS-COATED ACETABULAR COMPONENT WITHOUT SCREWS DURING SURGERY?

Background: Press-fit implantation of a porous-coated acetabular component without screws can be used for total hip arthroplasty (THA). The purpose of this report is to determine adequate initial stability of the acetabular component by applying a novel method would allow us to avoid screw use and to evaluate the outcomes of an oversized hemispherical cup using the 1 mm press-fit technique. Methods: We retrospectively evaluated 119 consecutive patients who underwent THA from February 2011 to June 2015. The intra-operative stability of fixation was checked by trying to pull the metal shell out of the acetabulum using the shell holder (pull-out test). We confirmed these tests using a digital hand scale. When we reached 9 to 10 kg (1 kg = 9.81 N), we showed that the acetabular shell achieved good stability. Kaplan-Meier survivorship analysis was performed to calculate the survival rate of the acetabular component. Results: The mean follow-up was 6.9 years (5–10 years). No component was revised because of loosening, and all implants were radiologically stable within the observation period. One socket had been revised because of failure of dislocation, which had [Formula: see text] acetabular inclination. There was an acetabular fracture in one hip, which was operated on prior to THA. Conclusions: We used a new method to assess the initial stability gained using the press-fit technique, which may allow the surgeon to determine whether adequate initial stability is achieved. Cup position has a significant impact on the risk of revision of press-fit cementless acetabular component. The risk for early failure can be decreased by optimal cup positioning during primary implantation. In addition, while a stable bone-implant connection is desirable, fracture of the acetabulum can be avoided using the 1 mm press-fit technique.

A 135° short inlay humeral stem leads to comparable radiographic and clinical outcomes compared with a standard-length stem for reverse shoulder arthroplasty.

BackgroundHumeral stem length in reverse total shoulder arthroplasty (RTSA) has decreased in recent years in an attempt to preserve more bone and facilitate stem removal in the revision setting. The purpose of this study was to compare the clinical and radiographic outcomes of a short- to standard-length stem RTSA. The authors hypothesized that there would be no difference in radiographic or clinical outcomes at short-term follow-up.MethodsPatients who underwent RTSA using a press-fit standard- or short-length humeral component with a consistent geometry (Univers Revers, or Revers Apex; Arthrex, Inc., Naples, FL, USA) were evaluated in a multicenter retrospective review. The minimum clinical follow-up was 2 years. Immediate postoperative radiographs were used to assess initial alignment and filling ratios. In addition, radiographs at 2 years were evaluated for signs of stress shielding and/or loosening. Clinical outcome scores and range of motion were evaluated at the final follow-up and compared between groups.ResultsA total of 220 patients with short-stem RTSA and 357 patients with standard-length stem RTSA were analyzed. There was no difference in baseline function between short- and standard-length stem patients. Patients in the short stem group had higher postoperative American Shoulder and Elbow Surgeons (84.6 vs. 80.8; P = .014) and Western Ontario Osteoarthritis of the Shoulder (86.5 vs. 82.7; P = .025). Patients in the short stem group also had greater postoperative active forward flexion (139° vs. 132°; P = .003) and internal rotation with the arm at 90° of abduction (43° vs. 32°; P < .001) than patients in the standard-length group. Radiographically, there was a higher metaphyseal (P = .049) and diaphyseal (P < .001) fill ratio in the short stem group, although there was no difference in postoperative alignment, radiographic signs of loosening, or revision for loosening between groups (all P > .05).ConclusionA short inlay stem leads to comparable radiographic findings and revision-free survival compared with a standard-length stem when placed with a press-fit technique for RTSA. Clinical outcomes are also equivalent or slightly improved with a short stem compared with a standard-length stem.

The Effects of Press-Fit Technique Combined with Tranexamic Acid on Duration of Surgery and Intraoperative Blood Loss in Primary Total Hip Arthroplasty.

Background: Prolonged operative time and blood loss may affect the success rate in total hip arthroplasty (THA). The aim of the current study was to evaluate the effects of the press-fit (PF) technique without screws combined with tranexamic acid (TXA) on operative time and intraoperative blood loss in THA.Methods: We retrospectively evaluated 114 hips treated with THA between March 2017 and January 2021 in this study. The patients were divided into three groups, including PF-TXA group, only PF group, and screw group. PF-TXA group received intravenous (IV) 1 g TXA 15 minutes before surgical incision, followed by a peri-articular 1 g/50 ml TXA. Only the PF group and screw group did not receive TXA. The primary outcome measures were operative time and intraoperative blood loss. Secondary outcomes included postoperative blood loss, hemoglobin and hematocrit levels, allogeneic blood transfusions, length of hospital stay, the Harris Hip Score (HHS), and thromboembolic complications.Results: Operative time was lower in the PF-TXA group than that in the only PF and the screw group (p=0.0001). Intraoperative blood loss was significantly different in the PF-TXA group compared with the only PF and the screw group (423 ml, 516 ml, and 534 ml; respectively). The patients who received the PF technique combined with TXA had significantly less hospital stay length than the only PF group and the screw group (p=0.021).Conclusion: The findings obtained in this study suggest that although only the PF technique can provide a shorter operative time compared to using screws, less blood loss may not be obtained using this technique in THA. PF technique combined with TXA significantly decreased operation time and intraoperative blood loss as well as the length of hospital stay following primary THA.

Low-dose Preoperative Unshielded Radiation Is Effective in Heterotopic Ossification Prophylaxis and Does Not Affect Porous Fixation in Total Hip Arthroplasty at 2 Years Minimum Follow-up: A Radiographic Study.

Heterotopic ossification (HO) is a frequent complication of total hip arthroplasty (THA). HO can cause pain, limitation of range of motion, and instability. Radiation therapy (RT) for HO prophylaxis is well established but may interfere with early porous ingrowth and pullout strength of implants, as suggested by two animal studies. Although shielding of the bone from irradiation may theoretically protect ingrowth, it has been found to reduce RT effectiveness. Despite the popularity of porous implants in THA, the frequency of HO, and use of RT in its prophylaxis, the effect of RT on porous implant fixation in THA has not been previously reported. At our institution, we use unshielded, single-dose, preoperative 700 to 800 centigrays RT for HO prophylaxis in high-risk patients. We hypothesize that this RT protocol is effective and the press-fit technique protects porous implants during early ingrowth; therefore, long-term implant fixation is not compromised. This was a retrospective study aiming to determine fixation of porous THA implants, healing of trochanteric osteotomies, and efficacy of HO prophylaxis with this RT protocol. Thirty-nine patients with follow-up of 24 to 144 months (average 59.7 months) were included. All 26 porous-coated femoral implants (11 revisions and 15 primary) were well fixed. There were 33 porous-coated acetabular implants (18 revisions and 15 primary). Thirty (91%) were well fixed, and three revision implants (9%) demonstrated radiolucent lines in two zones, but patients were clinically asymptomatic. All nine trochanteric osteotomies healed uneventfully. RT provided effective HO prophylaxis in 33 of 39 hips (85%). Single, low-dose, preoperative RT without shielding does not increase aseptic loosening of porous implants manufactured with plasma porous spray or nonunion of extended trochanteric osteotomies. This protocol provides effective HO prophylaxis in high-risk patients undergoing primary and revision THA.

Enhanced self-biased magnetoelectric response in novel distributed disc structure Ni/PZT composite

This article proposes a novel magnetoelectric (ME) composite configuration referred to as the Distributed Disc Structured (DDS) configuration. Ni/PZT ME composites have been fabricated using the press-fit technique, wherein the number of PZT discs have been sequentially increased to prepare 2-disc, 4-disc and 6-disc DDS configurations. The increase in the number of disc leads to an increase as well as a more uniform distribution of the inherent compressive prestress in the magnetostrictive phase which in turn leads to a significant enhancement in the self-biased and the overall ME behavior of the composite. A remarkable enhancement in the quasi-static and resonant ME voltage output is obtained from the proposed DDS configurations as compared to the conventional disc/ring configuration. Magnetostriction measurements have been conducted to validate the effect of the compressive prestress on the improvement in the ME response.

Novel press-fit technique of patellar bone plug in anterior cruciate ligament reconstruction is comparable to interference screw fixation.

Conventional press-fit technique for anterior cruciate ligament reconstruction (ACLR) is performed with extraction drilling of the femoral bone tunnel and manual shaping of the patellar bone plug. However, the disadvantages of this technique include variation in bone plug size and, thus, the strength of the press-fit fixation, bone loss with debris distribution within the knee joint, potential heat necrosis, and metal wear debris due to abrasion of the guide wire. To overcome these disadvantages, a novel technique involving punching of the femoral bone tunnel and standardized compression of the bone plug was introduced. In this study, the fixation strength and apparent stiffness were tested and compared to that of the gold-standard interference screw fixation technique in three flexion angle configurations (0°/45°/90°) in a porcine model. We hypothesized that the newly developed standardized press fit fixation would not be inferior to the gold standard method. Sixty skeletally mature porcine knees (30 pairs) were used. Full-thickness central third patellar tendon strips were harvested, including a patellar bone cylinder of 9.5mm in diameter. The specimens were randomly assigned to 10 pairs per loading angle (0°, 45°, 90°). One side of each pair was prepared with the press-fit technique, and the contra-lateral side was prepared with interference screw fixation. Equivalent numbers of left- and right-sided samples were used for both fixation systems. A three-way multifactor ANOVA was carried out to check for the influence of (a) fixation type, (b) flexion angle, and (c) side of the bone pair. The primary fixation strength of femoral press-fit graft fixation with punched tunnels and standardized bone plug compression did not differ significantly from that of interference screw fixation (p = 0.51), which had mean loads to failure of 422.4 ± 134.6N and 445.4 ± 135.8N, respectively. The flexion angle had a significant influence on the maximal load to failure (p = 0.01). Load values were highest in 45° flexion for both fixations. The anatomical side R/L was not a statistically significant factor (p = 0.79). The primary fixation strength of femoral press-fit graft fixation with punched femoral tunnels and standardized bone plug compression is equivalent to that of interference screw fixation in a porcine model. Therefore, the procedure represents an effective method for ACL reconstruction with patellar or quadriceps tendon autografts including a patellar bone plug.

Periprosthetic occult acetabular fracture: an unknown side effect of press-fit techniques in primary cementless total hip arthroplasty.

This study sought to investigate the prevalence and risk factors of periprosthetic occult acetabular fracture occurring during cementless acetabular cup insertion in patients undergoing primary total hip arthroplasty (THA) and to assess the clinical consequences of these fractures. A total of 232 hips (n = 205 patients) were included in this study. A periprosthetic occult acetabular fracture was defined as that which was unrecognised intraoperatively and was undetectable on post-operative radiographs yet was successfully diagnosed on post-operative computed tomography (CT) images. Clinical (age, sex, body mass index, and preoperative diagnosis) and surgical (additional screw fixation, cup rim size, and cup type) variables were analysed to identify risk factors for periprosthetic occult acetabular fracture. Sixteen (6.9%) periprosthetic occult intraoperative acetabular fractures were identified. In addition, one (0.4%) periprosthetic acetabular fracture was found during operation. The superolateral wall (9/16 hips; 56.3%) was the most frequent location. In addition, one (0.4%) periprosthetic acetabular fracture was found during operation. Male sex was the only factor associated with an increased risk for periprosthetic occult intraoperative acetabular fracture (odds ratio for male versus female sex: 4.28; p = 0.04). There was no significant association between cup type and the occurrence of periprosthetic occult acetabular fracture. All 16 hips with periprosthetic occult intraoperative acetabular fracture were healed at the final follow-up visit without the requirement for any additional surgical interventions. The results of the current study suggest that periprosthetic occult acetabular fractures are common during press-fit acetabular cup insertion in primary THA. Surgeons should have a high index of suspicion and early CT imaging referral in male patients who present with unexplained early post-operative groin pain in primary THA using cementless acetabular cups.

A novel press-fit minimally-invasive symphysiodesis technique

ObjectiveInstability of the pubic symphysis often results in a poor outcome and reduced mobility of the patient. In some cases, an arthrodesis of the pubic symphysis is required. Until today, there is no data published how many of these procedures are performed annually and there is also no data about the outcome after this extensive surgery.MethodsWe developed a novel surgical technique to address the arthrodesis of the pubic symphysis in a minimally invasive approach. Therefore, we used for this purpose modified instruments and performed the transplantation of a cylindrical bone substitute into the pubic symphysis, without an extensive approach or dissecting the anterior or posterior symphyseal ligaments.ResultsUsing this novel technique, a minimally invasive symphysiodesis was achieved in radiological findings, after the procedure.ConclusionThus, this actually minimally invasive surgical technique seems to be a promising advancement for the arthrodesis of the pubic symphysis.